The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art, or relevant, to the presently claimed inventions, or that any publication specifically or implicitly referenced is prior art. This application relates to peptide-based transfection vectors and research, diagnostic, medical, therapeutic, and cosmetic uses thereof.
A significant limitation for cellular research, and particularly medicine in the development of many therapeutic drugs, is the poor permeability of the cell membrane to outside agents. Efficient cellular uptake of many chemical agents is still a challenge. Several approaches have been tried, but all have limitations. One approach has made use of synthetic vectors derived from lipids such as liposomes (see, e.g., Leserman et al. (1980) Nature (London) 288, 602; Machy and Leserman, (1983), Biochim. Biophys. Acta, 730, 313), cationic lipids (see, e.g., Felgner et al., (1987) Proc. Natl. Acad. Sci. USA, 84, 7413; Behr et al. (1989) Proc. Natl. Acad. Sci. USA, 86, 6982; Demeneix et al. (1991) Int. J. Dev. Biol., 35, 481; Labat-Moleur et al. (1996), Gene Ther., 3, 1010; Zhou et al. (1994), Biochim. Biophys. Acta, 1189, 195; Radler et al (1997), Science, 275, 810) and polyethyleleimine (see, e.g., Boussif et al. (1996), Gene Ther., 3, 1074; Boletta et al., (1997), Hum. Gene Ther., 8, 1243). These, while demonstrated to be somewhat effective for the delivery of nucleic acids, have largely not proven successful delivering other types and sizes of compounds. Moreover, they represent foreign entities that will likely cause side effects and cellular toxicity.
Another approach has been the use of viral vectors. Although a powerful technology unto itself, this type of vector can only directly introduce nucleic acids, not proteins. Furthermore, these types of vector present difficulties, or at least apprehension, and hence reluctance, based on concerns of residual pathogenicity that might arise. So far, these safety concerns have yet to be adequately resolved.
Still another approach has been the use of microinjection, but this mechanical procedure is time consuming and not practical from the standpoint of delivery to whole populations of cells, and cells that may already be differentiated, or else in situ deep inside a patient.
More recently, vectors have been described that are based on peptides. However, these approaches are limited since the vectorization process has largely required covalent binding between the vector and the drug, diagnostic, and/or research compound sought to delivered. This applies to virtually all existing peptide strategies, including those employing polylysine (see, e.g., Leonetti et al. (1988), Gene, 72, 323; Degols et al. (1989) Nucleic Acids Res., 19, 945; Lemaitre et al. (1987), Proc. Natl. Acad. Sci. USA, 84, 648; and Degols et al. (1994), Bioconjug. Chem., 5, 8), fusion peptides (see, e.g., Pichon et al. (1997), Mol. Pharmacol., 51, 431; and Bongartz et al. (1994), Nucleic Acids Res., 22, 4681), peptides issued from the homeodomain of antennapedia (see, e.g., Derossi et al., (1996), J. Biol. Chem., 271, 18188; and Brugidou et al. (1995), Biochem. Biophys. Res. Commun., 214, 685) and short peptides such as KDEL (see Arar et al. (1995), Bioconjug. Chem., 6, 573), sequences related to the tat gene of HIV (Vives et al. (1997), J. Biol. Chem., 272, 16010), and more sophisticated “loligomer” peptides that contain a nuclear localization sequence associated with an oligolysine sequence (see Sheldon et al. (1995), Proc. Natl., Acad. Sci. USA, 92, 2056. Another vector has further made use of basic peptides (see, e.g., Niidome et al., H., 1997, J. Biol. Cham., 272, 15307; Haensler et al. (1993), Bioconjugate Chem., 4, 372; and Gottschalk et al. (1996), Gene Therapy, 3, 448). Finally, a short peptide has previously been shown to effectively deliver small oligonucleotides of 18-36 nucleotides in length when non-covalently associated therewith (Morris et al. (1997) Nucleic Acids Res., 25, 2730). Most, if not all, of these existing techniques are further limited by a lack of delivery efficiency, especially for large macromolecules, and further yet from compromised biological activity due to serum or medium sensitivity and cytotoxicity.
Thus alternative delivery schemes would be welcome, especially those that overcome one or more of the above noted deficiencies in the art. An ideal agent would have a good delivery efficiency for a broad spectrum of compounds and cell types, and would further have a low toxicity, be easy to handle, and easy to formulate in conjunction with the many different compound types that it can deliver.